Zbrasov Aragonite Caves
The warmest caves in the country, formed from below by mineral water, with pools of carbon dioxide on the floor.
Updated 19 October 2026
The Zbrasovske aragonitove jeskyne are hydrothermal: they were dissolved not by rainwater sinking from above but by warm mineral water and carbon dioxide rising from below, which is unusual and gives them their two distinguishing features. They are the warmest caves open in the country, staying around fourteen degrees all year, and they contain accumulations of carbon dioxide gas that pool in hollows and low chambers - the gas is heavier than air and lies in invisible lakes on the floor, monitored constantly, with parts of the system closed because of it. The decoration is aragonite rather than the usual calcite, forming needle and shrub-like clusters, along with sinter and geyser-type formations. Above the caves is the Hranicka propast, an abyss whose flooded shaft has been probed by divers and remote vehicles past four hundred metres and is among the deepest known freshwater cavities in the world.
History
In December 1912 workers at a local quarry uncovered a crack in the rock with warm air coming out of it. The brothers Josef and Čeněk Chromý, interested in the local karst, widened the opening and in January 1913 climbed down a rope 42 m into the darkness; the rope broke, their carbide lamps were smashed in the fall, and they waited eight hours in the dark to be rescued. Over the following years they and other members of the local volunteer miners explored the 1,322 m cave system in their free time, a more convenient entrance was dug from the Bečva valley, electric light was installed, and the caves opened to the public in 1926. From 2002 to 2005 the paths and wiring were renewed and much rock debris left from the original entry works was removed, returning parts of the system to their natural form (Wikipedia, Zbrašov Aragonite Caves).
Highlights
- Warm caves - around fourteen degrees all year, dissolved by rising mineral water.
- Carbon dioxide lakes - invisible gas pooling in hollows, monitored constantly.
- Aragonite clusters - needle and shrub forms rather than ordinary dripstone.
- Hranicka propast above - a flooded abyss among the deepest known in the world.
When to go
All year. Two hours.
Before you go
Guided tours only and busy in summer. Parts of the system are permanently closed because of the gas. The abyss itself is not visitable - it is viewed from a platform above. Steps throughout.
Nearby
Teplice nad Becvou spa is at the entrance; Hranice is three kilometres away.
Key facts
Source: Wikidata, item Q168272, read on 18 October 2026.
What to pack for Zbrasov Aragonite Caves
Chosen from what this place is for. Tap a kit for the full checklist.
- Your own mask + snorkel - A well-fitting mask is the single biggest comfort upgrade underwater. Find on Amazon
- Head torch + spare batteries - Hands-free light is essential; caves are truly dark. Find on Amazon
- Swimwear - Needed at most public thermal pools; some traditional baths are nude and single-sex. Find on Amazon
- Rash guard or thin wetsuit - Sun cover on the surface and warmth on longer or deeper dives. Find on Amazon
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